If you are an ISV, you should seriously take a look at SQL Server 2005. It's available now for MSDN subscribers. SQL Server has a host of new features, including deep integration with Visual Studio and .NET. These two features make SQL Server 2005 the most productive database to develop in.
If you don't have access to MSDN downloads, take SQL Server Express for a test drive. Express has many of the same capabilities as SQL Server 2005 Standard(except for the high-end enterprise features).